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New measurement of D0 and D+ meson masses with the KEDR detector

KEDR Collaboration, V. V. Anashin, O. V. Anchugov, A. V. Andrianov, K. V. Astrelina, V. M. Aulchenko, E. M. Baldin, G. N. Baranov, A. K. Barladyan, A. Yu. Barnyakov, M. Yu. Barnyakov, S. E. Baru, I. Yu. Basok, A. M. Batrakov, I. V. Bedny, E. A. Bekhtenev, O. V. Belikov, D. E. Berkaev, A. E. Blinov, V. E. Blinov, M. F. Blinov, A. V. Bobrov, V. S. Bobrovnikov, A. V. Bogomyagkov, D. Yu. Bolkhovityanov, S. I. Eidelman, A. E. Bondar, D. V. Bondarev, A. R. Buzykaev, P. B. Cheblakov, V. L. Dorohov, F. A. Emanov, V. V. Gambaryan, Yu. M. Glukhovchenko, D. N. Grigoriev, V. V. Gulevich, D. V. Gusev, V. V. Kaminskiy, S. E. Karnaev, S. V. Karpov, G. V. Karpov, K. Yu. Karukina, D. P. Kashtankin, P. V. Kasyanenko, A. A. Katcin, T. A. Kharlamova, V. A. Kiselev, S. A. Kononov, K. Yu. Kotov, A. A. Krasnov, E. A. Kravchenko, V. N. Kudryavtsev, V. F. Kulikov, G. Ya. Kurkina, E. A. Kuper, I. A. Kuyanov, E. B. Levichev, P. V. Logachev, D. A. Maksimov, T. V. Maltsev, Yu. I. Maltseva, V. M. Malyshev, A. L. Maslennikov, A. S. Medvedko, O. I. Meshkov, S. I. Mishnev, I. A. Morozov, I. I. Morozov, N. Yu. Muchnoi, V. V. Neufeld, D. A. Nikiforov, S. A. Nikitin, I. B. Nikolaev, I. N. Okunev, A. P. Onuchin, S. B. Oreshkin, I. O. Orlov, A. A. Osipov, I. V. Ovtin, A. V. Pavlenko, S. V. Peleganchuk, K. G. Petrukhin, P. A. Piminov, S. G. Pivovarov, A. O. Poluektov, I. N. Popkov, V. G. Prisekin, O. L. Rezanova, A. A. Ruban, V. K. Sandyrev, G. A. Savinov, A. G. Shamov, E. A. Simonov, D. N. Shatilov, L. I. Shekhtman, D. A. Shvedov, B. A. Shwartz, Yu. I. Skovpen, A. N. Skrinsky, V. V. Smaluk, A. V. Sokolov, S. V. Sinyatkin, D. P. Sukhanov, A. M. Sukharev, A. A. Talyshev, E. V. Starostina, V. I. Telnov, Yu. A. Tikhonov, K. Yu. Todyshev, A. G. Tribendis, V. A. Tayursky, G. M. Tumaikin, Yu. V. Usov, A. I. Vorobiov, A. N. Yushkov, V. N. Zhilich, A. A. Zhukov, V. V. Zhulanova, A. N. Zhuravlev, D. A. Zubkov

TL;DR

This work reports precise measurements of the neutral and charged D meson masses using near-threshold $e^+e^-\to D\overline{D}$ production at the ψ(3770) with the KEDR detector at VEPP-4M. The analysis employs beam-constrained mass $M_{bc}$ and energy constraints, with a specialized treatment for $D^0\to K^-\pi^+$ that includes a $\Delta|p|$-based separation, and a two-variable fit for $D^+\to K^-\pi^+\pi^+$; two data samples (0.9 and 4.0 pb^-1) collected in 2004 and 2016–2017 are reprocessed and combined. Corrections for ISR/FSR, momentum calibration via the scale factor $\alpha$, and detailed MC-based PDFs enable a robust unbinned likelihood extraction of the masses, with a careful assessment of systematic uncertainties. The final results are $M_{D^0}=1865.100\pm0.210_{stat}\pm0.046_{syst}$ MeV, $M_{D^+}=1869.560\pm0.288_{stat}\pm0.109_{syst}$ MeV, and $M_{D^+}-M_{D^0}=4.46\pm0.36_{stat}\pm0.12_{syst}$ MeV, which improve the direct $D^+$ mass precision and are consistent with PDG values. This work demonstrates the viability of high-precision hadron-mass measurements at a low-energy collider with meticulous detector calibration and systematic handling.

Abstract

Using the 4.9 pb$^{-1}$ statistics collected at the peak of the $ψ(3770)$ resonance with the KEDR detector at the VEPP-4M electron-positron collider, we measured the masses of the neutral and charged D mesons: $M_{D^0} = 1865.100 \pm 0.210 (stat) \pm 0.046 (syst) MeV,$ and $M_{D^+} = 1869.560 \pm 0.288 (stat) \pm 0.109 (syst) MeV$.

New measurement of D0 and D+ meson masses with the KEDR detector

TL;DR

This work reports precise measurements of the neutral and charged D meson masses using near-threshold production at the ψ(3770) with the KEDR detector at VEPP-4M. The analysis employs beam-constrained mass and energy constraints, with a specialized treatment for that includes a -based separation, and a two-variable fit for ; two data samples (0.9 and 4.0 pb^-1) collected in 2004 and 2016–2017 are reprocessed and combined. Corrections for ISR/FSR, momentum calibration via the scale factor , and detailed MC-based PDFs enable a robust unbinned likelihood extraction of the masses, with a careful assessment of systematic uncertainties. The final results are MeV, MeV, and MeV, which improve the direct mass precision and are consistent with PDG values. This work demonstrates the viability of high-precision hadron-mass measurements at a low-energy collider with meticulous detector calibration and systematic handling.

Abstract

Using the 4.9 pb statistics collected at the peak of the resonance with the KEDR detector at the VEPP-4M electron-positron collider, we measured the masses of the neutral and charged D mesons: and .

Paper Structure

This paper contains 9 sections, 18 equations, 7 figures, 3 tables.

Table of Contents

  1. Introduction
  2. VEPP-4M collider and KEDR detector
  3. Data samples
  4. Measurement method
  5. Analysis of $D^0\rightarrow K^-\pi^+$
  6. Analysis of $D^+\rightarrow K^-\pi^+\pi^+$
  7. Study of systematic uncertainties
  8. Weighting of results on masses
  9. Conclusion

Figures (7)

  • Figure 1: The central part of the KEDR detector: (1) vacuum chamber of the collider; (2) vertex detector; (3) drift chamber; (4) aerogel threshold Cherenkov counters; (5) time of flight counters; (6) liquid krypton barrel calorimeter; (7) superconductive solenoid; (8) magnet yoke; (9) muon chambers; (10) endcap CsI calorimeter; (11) compensating coil.
  • Figure 3: The distributions of $M_{\rm bc}$, $\Delta E$, $\Delta|p|$ and correlation $M_{\rm bc}$--$\Delta E$ from MC simulated signal sample. The blue dots with error bars are from MC simulation, the solid red line is the fitting result.
  • Figure 4: The distributions of $M_{\rm bc}$, $\Delta E$ and correlation $M_{\rm bc}$--$\Delta E$ from MC simulated continuum $e^+e^-\to q\bar{q}$ (where $q=u,d,s$) background sample. The blue dots with error bars are from MC simulation, the solid red line is the fitting result.
  • Figure 5: The distributions of $M_{\rm bc}$, $\Delta E$ and correlation $M_{\rm bc}$--$\Delta E$ from MC simulated $D\overline{D}$ background sample. The blue dots with error bars are from MC simulation, the solid red line is the fitting result.
  • Figure 6: Experimental data (points with the error bars) and the results of the fit (histogram) for the $D^0\rightarrow K^-\pi^+$ decay. $M_{\rm bc}$ distribution for events with $|\Delta E|<$100 MeV (left), $\Delta E$ distribution for events with 1855 MeV$<M_{\rm bc}<$1875 MeV (middle), and the experimental ($M_{\rm bc}$, $\Delta E$) scatter plot (right). The top pictures correspond to the first data sample (2004), the bottom pictures correspond to the second data sample (2016-2017).
  • ...and 2 more figures